1. Field of the Invention
This invention relates to spectrometric analysis, and more particularly, to an assembly for concentrating sulfuric acid and like high boiling materials for subsequent spectrometric analysis.
2. Description of Prior Art
Analyzing concentrated chemicals using spectrometric techniques usually requires the concentration (or "prepping") of the chemical sample by evaporation to a weight of a known ratio to the weight of the original sample. Such procedure allows the sample to be analyzed since it reduces the concentration of the chemical (also known as matrix removal) as well as concentrate trace contaminants thereby permitting analysis of low levels.
Prepping of sulfuric acid is particularly troublesome since high temperatures are required with concomitant evolution of toxic fumes. Originally, prepping was performed in open vessels in a clean room hood. Subsequently, prepping involved the use of a covered vessel or assemblies. These are disclosed vessel types used in chemical analysis, such as in U.S. Pat. No. 3,324,628 to Nelson; U.S. Pat. No. 4,703,935 to Scherping, U.S. Pat. No. 4,837,161 to Stevens et al. and U.S. Pat. No. 4,401,625 to Willay et al.
The handling of the toxic fumes constantly presented a problem, such as, for example, by leakage through gaskets and the like. Use of inert gas flow and the like proved unsuccessful as well as the inability of vessel assemblies to maintain gaseous integrity at the high temperature levels required for sulfuric acid prepping.